Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038187 (starvation)
 24,951 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many previous studies have demonstrated that antisense oligodeoxynucleotides (ODNs) bind to surface proteins in a manner compatible with receptor-mediated endocytosis and, unless specifically modified, are internalized into endosomes with little access to the cytoplasmic structures or to the nucleus. Reports vary as to the specific proteins involved in the mechanism, and this study examines the conditions of binding, some proteins that might contribute to the process, and whether changes in binding patterns occur during differentiation. Native gel electrophoresis was used to optimize the surface binding of a phosphorothioate end-capped 16-mer to T15 mouse fibroblast cells, and comparisons are made with some human epithelial tumor cell lines. Binding to individual proteins was visualized using SDS-PAGE and autoradiography. Binding at 4 degrees C was almost exclusively to a 46 kDa protein and decreased in the presence of an excess of unlabeled ODN and heparin but not ATP. Increasing the temperature of ODN binding from 4 degrees C to 37 degrees C for 10 minutes changed the binding pattern observed. ODN binding to the total cytoplasmic and membrane proteins immobilized on a membrane showed a greater number of binding proteins, the most prominent being one of 30 kDa. Examination of the effects of serum on binding were made using the human lung carcinoma cell line COR-L23, which can be grown in serum-free conditions. Serum starvation led to an increased total binding seen on native gels coinciding with increased binding to a 46 kDa protein. Demonstration that changes in binding proteins occur when cells differentiate was made using the premacrophage cell line THP-1. Differentiation of these cells increased the total ODN binding and appeared to initiate the synthesis of some new binding proteins, although binding to a 46 kDa protein was reduced.
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PMID:Interaction of oligodeoxynucleotides with mammalian cells. 891 3

An endopeptidase (designated RSIP, for root-starvation-induced protease) was purified to homogeneity from glucose-starved maize roots. The molecular mass of the enzyme was 59 kDa by SDS/PAGE under reducing conditions and 62 kDa by gel filtration on a Sephacryl S-200 column. The isoelectric point of RSIP was 4.55. The purified enzyme was stable, with no auto-proteolytic activity. The enzyme activity was strongly inhibited by proteinaceous trypsin inhibitors, di-isopropylfluorophosphate, 3,4-dichloroisocoumarin and PMSF, suggesting that the enzyme is a serine protease. The maximum proteolytic activity against different protein substrates occurred at pH 6.5. With the exception of succinyl-Leu-Leu-Val-Tyr-4-methylcoumarin, no hydrolysis was detected with synthetic tryptic, chymotryptic or peptidylglutamate substrates. The determination of the cleavage sites in the oxidized B-Chain of insulin showed specificity for hydrophobic residues at the P2 and P3 positions, indicating that RSIP is distinct from other previously characterized maize endopeptidases. Both subcellular fractionation and immuno-detection in situ indicated that RSIP is localized in the vacuole of the root cells. RSIP is the first vacuolar serine endopeptidase to be identified. Glucose starvation induced RSIP: after 4 days of starvation, RSIP was estimated to constitute 80% of total endopeptidase activity in the root tip. These results suggest that RSIP is implicated in vacuolar autophagic processes triggered by carbon limitation.
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PMID:Purification and biochemical characterization of a vacuolar serine endopeptidase induced by glucose starvation in maize roots. 894 99

A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1, expressed at phosphate concentrations below 0.08-0.13 mM, was purified and characterized. The purification method involved separation of outer-membrane proteins by SDS-PAGE and extraction of the protein from nitrocellulose or PVDF membranes after electrotransfer of proteins to the membranes. The N-terminal amino acid sequence of the purified protein, called Psi1, did not show homology to any known proteins, and in contrast to the phosphate-specific porin OprP of P. aeruginosa its mobility in SDS-PAGE was not affected by solubilization temperature. An antiserum against Psi1 recognized a protein of M, 55,000 in four other P. fluorescens strains among 24 tested strains representing Pseudomonas rRNA homology group I, showing antigenic heterogeneity within this group. A method for immunofluorescence microscopy involving cell permeabilization was adapted to visualize cell-specific expression of Psi1 in P. fluorescens exposed to limiting amounts of phosphate. This approach should be useful for further exploration of Psi1 as a marker to study the availability of phosphate to P. fluorescens in natural environments.
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PMID:A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1 as an immunological phosphate-starvation marker. 908 84

A technique for detection of the activity of hydroxylamine oxidoreductase (HAO) involving denaturing SDS-polyacrylamide gels was developed. The activity of HAO of Nitrosomonas europaea was assayed using this technique, which revealed a single active band of 140 kDa. The HAO activity of other ammonia-oxidizers was also resistant to SDS, the molecular weights being identical to that of N. europaea. N. europaea cells starved of ammonia for up to 72 h retained a considerable amount of HAO, as detected on Western blot analysis, and a significant level of its activity, as found on assaying at the end of the starvation period. Only after 4 h incubation of starved N. europaea cells with 2.0 mM ammonia was some increase in the HAO level observed. The results indicate that HAO remains highly stable during ammonia starvation of N. europaea.
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PMID:Effect of ammonia starvation on hydroxylamine oxidoreductase activity of Nitrosomonas europaea. 919 39

Bacteroides fragilis strains isolated from different sources, i.e. 1 strain (AA1) from an aquatic environment, 1 strain from normal flora (118310) and the type strain (ATCC 25285) originally isolated from clinical material, were analysed for both cell envelope proteins composition and surviving under oxidative stress starvation. All strains examined showed a similar survival response when cultured in drinking water with a ten-fold decrease in viable counts per day during the 7 days of analysis. The outer membrane protein (OMP) profiles of all strains were quite similar during the stress period as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). However, the periplasmic proteins of the strain 118310 showed two protein bands at 48 and 58 kDa, respectively, that were absent in the strains AA1 and ATCC 25285 during the incubation period in potable water. Whole cells and periplasmic 35S-labelled proteins from bacteria cultured in drinking water showed a significant increase in proteins at 16, 18, 24, 26, 35, 48, and 58 kDa and 18, 22, 24, 48, 58, and 70 kDa, respectively, in all strains when compared to cells grown in BHI-PRAS media as detected by autoradiography following SDS-PAGE. These data suggest that B. fragilis may have a synthesis mechanism that allows them to adapt to adverse environments.
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PMID:Influence of stress conditions on Bacteroides fragilis survival and protein profiles. 963 69

Axenic cultures of the ammonia-oxidizing bacterium Nitrosomonas europaea were starved of ammonia (energy source) for up to 342 d. During this time the bacteria retained the ability to respond instantly to ammonia (1 mM) or hydroxylamine (0.1 mM) amendment by oxidizing it to nitrite without initial protein synthesis. In vivo, the ability to oxidize amended ammonia stayed almost constant during the starvation period, but a drop in the hydroxylamine oxidation rate (to 33%) was observed after 4 wk of starvation when exogenous hydroxylamine was supplied as sole energy source. In contrast, it has been shown that the level and in vitro activity of hydroxylamine oxidoreductase were not significantly affected during the starvation period. Only minor changes were detected between the protein patterns on one-dimensional SDS-PAGE of growing and starved cells. Thus, it is concluded that the activities of the energy-generating enzymes in N. europaea were not affected during long-term ammonia starvation.
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PMID:Effect of long-term ammonia starvation on the oxidation of ammonia and hydroxylamine by Nitrosomonas europaea. 975 28

Plasmodial transglutaminase of Physarum polycephalum was purified by anion exchange and hydrophobic chromatography. Gel filtration and SDS-polyacrylamide gel electrophoresis indicate that it is a monomer of 96-101 kDa. It is Ca2+-dependent, with half-maximal activity at 0. 7 mM Ca2+. Optimal activity occurs at pH 7.5 and at 50 mM KCl. Inactivation by N-ethylmaleimide indicates that it is a thiol enzyme. With N,N-dimethylcasein as substrate, the Km for monodansylcadaverine is 33.9 +/- 1.8 microM. Damage of plasmodia by brief treatment with 15% ethanol activates the transglutaminase, with rapid accumulation of cross-linked proteins unable to enter gels during SDS-polyacrylamide gel electrophoresis. Added monodansylcadaverine is conjugated principally to LAV1-2, a plasmodia-specific 40-kDa protein with four EF-hand sequences believed to bind Ca2+. Actin is seen as an additional substrate only in plasmodial homogenates. Immunoblots show that upon ethanol treatment, a portion of LAV1-2 is modified quickly and shifts to 36 kDa; another portion is cross-linked to itself or other proteins. The modification of LAV1-2 may lead to localized release of Ca2+ and activation of transglutaminase for walling off damaged areas of plasmodia. No significant increase in amount of the transglutaminase occurs during starvation-induced differentiation of plasmodia to form spherules, but a 50% reduction in the amount of total protein leads to a doubling in the specific mass of the TGase. Neither the transglutaminase nor LAV1-2 is found in the ameboid form of the organism.
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PMID:Characterization of 101-kDa transglutaminase from Physarum polycephalum and identification of LAV1-2 as substrate. 979 6

Proteins from white muscle are mobilized to cover energy requirements during long-term starvation in fish. Using SDS-polyacrylamide gel electrophoresis, we compared the soluble and insoluble fractions of white muscle proteins from fed and starved Atlantic cod, Gadus morhua, to establish whether preferential preservation or degradation of specific proteins occurred during starvation. While starvation induced no qualitative changes in the electrophoretic pattern of the myofibrillar fraction, our results document differential decreases in the levels of soluble proteins during fasting. Moreover, immunoblot analysis using a monoclonal antibody directed against actin, showed a marked accumulation of this protein in the sarcoplasmic fraction of starved individuals, most likely due to myofibrillar degradation.
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PMID:Changes in qualitative composition of white muscle with nutritional status of Atlantic cod, Gadus morhua. 988 75

The Saccharomyces cerevisiae gene YNL234w encodes a 426-amino acid-long protein that shares significant similarities with the globin family. Compared with known globins from unicellular organisms, the Ynl234wp polypeptide is characterized by an unusual structure. In this protein, a central putative heme-binding domain of about 140 amino acids is flanked by two sequences of about 160 and 120 amino acids, respectively, which share no similarity with known polypeptides. Northern analysis indicates that YNL234w transcription is very low in cells grown under normal aerobic conditions but is induced by oxygen-limited growth conditions and by other stress conditions such as glucose repression, heat shock, osmotic stress, and nitrogen starvation. However, the deletion of the gene had no detectable effect on yeast growth. The Ynl234wp polypeptide has been expressed in Escherichia coli, and the hemoprotein nature of the recombinant protein was demonstrated by heme staining after SDS/polyacrylamide gel electrophoresis and spectroscopic analysis. Our data indicate that purified recombinant Ynl234wp possesses a noncovalently bound heme molecule that is predominantly found in a low spin form.
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PMID:Characterization of a new hemoprotein in the yeast Saccharomyces cerevisiae. 998 49

Development of mating competency in Tetrahymena thermophila requires starvation for at least 70 min in low ionic strength buffer. Pair formation between conjugating cells is blocked at early stages by the lectin Concanavalin A (Con A). To investigate the role of Con A-binding proteins in this induced cellular change and pairing, and to confirm and extend an earlier study from our laboratory, a method was developed for preparation of Con A-binding proteins from ciliary membrane-rich fractions of T. thermophila. Con A-binding ciliary proteins were prepared from non-starved and starved cells from two wild type strains and a mating mutant, RH179E1. Comparison of these proteins by SDS-PAGE revealed on overall reduction in number of wild-type bands after starvation. In particular, a major band at 28 kDa was present in non-starved cells and absent in starved cells. However, in the mating mutant, no change in banding profile was seen after starvation: the 28 kDa band was present in both non-starved and starved cells. This, Con A-binding ciliary membrane proteins undergo a major change during starvation-induced development of mating competency in wild-type T. thermophila. In contrast, the mutant differed from wild-type in overall composition of its ciliary Con A-binding glycoproteins and in the response of these proteins to starvation, suggesting that it may be deficient in its ability to be initiated by starvation. Our results are consistent with the hypothesis that a change affecting ciliary membrane Con A-binding proteins is essential for the cellular response to mating signals.
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PMID:Affinity-purification of concanavalin A-binding ciliary glycoconjugates of starved and feeding Tetrahymena thermophila. 1036 35


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